This question has come up before, but Ive never seen it actually answered properly. The replies usually go off into never-never land on one tangent or another, concerning the environmental concerns of dumping fix, or the attributes of 2 fixer baths, or detailed descriptions of how I process film, but never have I seen an actual answer for the question.
Here it is:
How does one make a one-shot fixer just strong enough to do the job, and then be discarded?
For example, I use Kodak Rapid Fixer, so how much solution A is minimum (diluted with enough water to cover 120 roll film) to effectively fix the film only used one-shot and then dumped? Or how much solution A (diluted to sufficient volume) is required to fix one 8x10 sheet of film?
This would be economical for those of us who process just occasionally and prevent worrying about deterioration of stored working solutions. It seems prepared working solutions do not last very long per the data sheets.
I figured about 10cc of solution A SHOULD fix one roll of 120 film, but it would be diluted to 400cc to cover the film (in my tank), so it is a 1:39 dilution. WOULD this work as long as enough TIME is given in the bath? Or is the actual CONCENTRATION too weak to do a proper job?
So does the chemistry of fixation change because of the weak dilution, and is a full strength working solution necessary?
Surely someone has worked out this problem and has experiences to relate.